Planooraph co



J. W. LINDBERG.

DEVICE FOR SECURING KEYS IN LOCKS.

APPLICATION HLED MAR. 10. 1919.

1,314,526. PatentedSept. 2,1919.

Invenfon Johan Waldemar Lindberg THE DOLIJMIIA PIANOGRAPN C0-IIAININGTON, D- C.

PATENT OFFICE.

CFO-HAN WALDEMAR LINDBERG, OF STOCKHOLM, SWEDEN.

DEVICE FOR SECURING KEYS IN LOCKS.

Specification of Letters Patent.

Patented Sept. 2, 1919.

Application filed March 10, 1919. Serial No. 281,728.

To all whom it may concern:

Be it known that I, JonAN VALDEMAR Linonnne, a Subject of the King ofSweden, residing at Stockholm, in the Kingdom of Sweden, have invented anew and useful Improvement in Devices for Securing Keys in Locks, ofwhich the following is a specificatien.

The present invention refers to a device for securing keys in locks, andhas for its purpose to provide a device which makes it impossible toopen the door by means of a pick from the opposite side of the door. Forthe said purpose it has been proposed to use devices: consisting of astem to be introduced into the portion of the key-hole corresponding tothe key-bit, and a member gripping the key between the key-handle andthe lock, so that when the lock is bolted the key is prevented frombeing pushed out of the key-hole. Heretofore known devices of this kind,however, have the disadvantage of not being capable of preventing quitepositively the breaking open of the door. There are key-holes ofdifferent widths, and the stem to be slipped into the key-hole cantherefore not be made in such manner that it fills the key-holecompletely in every case, consequently, said stem can not prevent theintroduction of a pick through the key-hole. The old devices being soconstructed that it is not quite impossible by means of a pick thusintroduced to. open the member grippingthe kev and to release it fromengagement with the key, it will he understood that said old devicesare. not quite reliable.

The present invention has. for its purpose to. avoid the said.disadvantage with the 01d devices. The invention is broadlycharacterized by this that the member gripping the key consists of aplate approximately perpendicular to the key-shank, a portion of saidplate being made as a movable latch or the like capable of grippingaround the keyshank and of being secured in such position of engagementby means of a stop device or catch arranged on the side of said platedirected from the key-hole; Said plate thus renders it impossible toreach the catch with a pick introduced through the key-hole,consequently it prevents an undue opening of the latch gripping the key.

An embodiment of the invention is illustrated in the accompanyingdrawing by way of example. Figure 1 shows a plan view of the device.Fig. 2 shows a front view of the device when in use, and Fig. 3 shows afront view of the device with opened latch. Fig. 4 shows a side view ofthe device.

The device illustrated in the drawing consists of a stem 1 fitting intothe keyhole below the shank of a key introduced into said hole. The rearportion of said stem has suitably a somewhat enlarged cross section, asshown in Fig. 1, in order better to fill out the key-hole and thusrender it more diflicult to introduce a burglars tool, but the stem mayhave uniform cross section throughout its entire length. At the rear endof said stem 1 a plate 2 is secured perpendicularly to the stem, saidplate supporting by means of a stud 3 a latch t forming in position ofengagement as shown in Figs. 2 and 4, an upward continuation of theplate 2. lVhen the lock has been bolted and the kcy turned in suchmanner that the key-bit and thus also the key-handle or how areapproximately horizontal, the stem 1 is introduced into the hole in thekoy'cscutchoon 7 below the key, and afterward the latch 4 is swung downso that it grips around the shank of the key 5 back of the key-handle,that is to say, between said handle and the door, as shown in Figs. 2and 4. ltis now impossible to push out the stem 1 from the opposite sideof the door, as the latch 4 will become forced against the handle of thekey which is socured by the key-bit in the lock. Assuming that the keyhas been turned twice in the lock and that the stem 1 is suflicicntlylong to reach in under the portion of the keyshank where the key-bit issecured, it is even then not possible to open the look from the outsideof the door by turning the key by means of a burglars tool, because evenif the key was successfully turned so that the bolt of the look wasdrawn back one step the key-bit would afterward strike against the stem1 thus preventing further turning of the key.

In order to prevent any turning of the key and thus to make itimpossible to open the look by means of a pick even if the key had onlybeen turned once, a second plate 6 is secured at approximately rightangles to the plate 2. lNhen the device has been introduced into thekey-hole the said plate 6 will be approximately parallel to thekeyhandlo. If it is attempted to turn the key from the outside, thekey-handle will be caused to bear against the plate 6 whereby itsfurther turning will be prevented.

In the latch 1 there are cuts or notches 8 which will come exactlyopposite the keyhandle when the latch i swung down over the key-shank,as shown in Fig. 2. If it is now tried from the outside of the door topush the device out of the lock toward the inside of the door, thedevice will slide outward on the key which is held immovably in thelook, so that the said cuts or notches 8 will engage the two halves ofthe keyhandle projecting to either side of the key- I shank and thusprovide a still more positive engagement between the device and the key.But for said notches 8 it would not be quite out of the question, by anattempt to push the-device out of the key-hole from the outside of thedoor, if the edges of the keyhandle adjacent the key-shank are not quitein alinement and perpendicular to the key-shank but form a more or lessacuteangle with one another, that the said edges would act as a wedge inthe cut or opening 9 of the latch and thus raise the latch. If thedevice is used for a key-hole which is so large that it is not quitefilled out by the stem 1, but there being a clearance between said stemand one wall of the key-hole, there would be a possibility of reachingthe latch 4; and to raise it by means of a burglars tool from theoutside of the door, in which case the device could be detached from thekey and pushed out of the key-hole. In order to provide against suchpossibility a catch 12 is pivoted on a stud 11 on the side of the plate2 directed fromthe key-hole, said catch being maintained by a spring 13bearing against the bent edge 14 of the plate 2 in such normal positionas to project into the path of turning of a portion of thelatch 4 andthus in such position to prevent the turning of the latch 4, as willbe'understood from Fig. 2. The catch 12 is provided with a projectinglug 15 by means of which the catch 12 may be turned in such manner thatits end projecting into the said path of movement of said latch 4 willbe moved out of said path of movement, as shown in Fig. 3, after whichit is possible to turn the latch 1 on the stud 3, so that the device maybe detached from the key and pulled out of the key-hole, or introducedinto the same. When the device has been introduced and the latch 4 hasbeen turned down so as to engage the key, the catch 12 willautomatically be moved by the spring 13' into such position as to securethe latch 4. The plate formed by the members 2 and t now lies betweenthe key-hole and the catch '12, thus making it impossible to reach thecatch by means of a pick introduced through the keyhole.

It will be understood that'the invention is not limited to theembodiment illustrated in the drawing, .as various changes andmodifications may be made therein without departing from the spirit ofthe invention as defined in the appended claims.

I claim:

1. In a device for securing keys in locks, the combination of a stemadapted to be introduced into a key-hole, a plate secured approximatelyperpendicularly to said stem, a

latch attached to said plate so as to be movable in a planeapproximately perpendicu lar to said stem and adaptedto grip around theshank of a key, and means on the side of said plate opposite said stemfor securing said latch in operative position. 7

2; In a device for securing keys in locks, the combination of a stemadapted to be introduced into a key-hole, a plate secured ap proximatelyperpendicularly to said stem, a latch attached to said plate so as to bemovable in a plane approximately perpendicular to said stem and adaptedto grip around the shank of a key, said latch being provided.

with notches in such manner that in operative position of the latchsaidnotches are located opposite the handle of the key when turned inthe lock, and means on the side of said plate opposite said stem forsecuring said latch in operative position. I

3. In a device for securing keys in looks, the combination of a stemadapted to be introduced into a key-hole,a plate secured approximatelyperpendicularly to said stem, a

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, I). G.

